Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Mean platelet volume, an indicator of platelet reactivity, is increased in patients with patent foramen ovale Ercan Varol, Bayram A. Uysal, Ibrahim Ersoy, Mehmet Ozaydin, Dogan Erdogan and Abdullah Dogan Numerous studies have shown an association between patent foramen ovale (PFO) and cryptogenic stroke suggesting that paradoxical emboli may be an important cause of stroke. In addition, some authors have proposed that platelet activation is present in PFO patients and this might be the cause of the stroke. The aim of this study was to assess the mean platelet volume (MPV), an indicator of platelet activation and/or reactivity in patients with PFO. The study group consisted of 77 patients with PFO. An age, sex, BMI-matched control group was composed of 43 healthy volunteers. We measured serum MPV values in patients and controls. MPV was significantly higher among PFO patients when compared with control group (9.0 W 0.8 vs. 8.3 W 0.9 fl, respectively; P < 0.001). We have shown that MPV was significantly elevated in patients with PFO compared with controls. Blood Coagul Fibrinolysis 24:605–607 ß 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins. Blood Coagulation and Fibrinolysis 2013, 24:605–607 Keywords: mean platelet volume, patent foramen ovale, platelet activation, stroke Department of Cardiology, Suleyman Demirel University, Isparta, Turkey Correspondence to Ercan Varol, Department of Cardiology, Suleyman Demirel Univesitesi Tip Fakultesi, Isparta, Turkey Tel: +90 246 211 9346; e-mail: drercanvarol@yahoo.com Received 12 December 2012 Revised 13 February 2013 Accepted 13 February 2013 Introduction Approximately 25–40% of strokes are of undetermined pathogenesis, and are commonly termed cryptogenic strokes. Numerous studies have shown an association between patent foramen ovale (PFO) and cryptogenic strokes suggesting that paradoxical emboli (i.e. emboli crossing from the venous to arterial circulation through a PFO may be an important cause of cryptogenic strokes [1–5]. On the contrary, two prospective studies failed to confirm PFO as an independent risk factor for crypto- genic strokes, with only an insignificant trend toward a higher incidence of stroke in persons with PFO [6,7]. Mean platelet volume (MPV) is a simple and easy method of assessing platelet function [8,9]. In comparison to smaller ones, larger platelets have more granules, aggregate more rapidly with collagen, have higher thromboxane A2 level and express more glycoprotein Ib and IIb/IIIa receptors [10–12]. It has been accepted that PFO is a potential route for embolic transit of platelet aggregations, thrombi, gas bubbles or other particulate matter from the systemic venous circulation to the brain. PFO also could be a nidus for potentially embolic thrombus formation in situ [13]. To the best of our knowledge, there is no data assessing MPV, an indicator of platelet activation and/or reactivity in patients with PFO. In this study, we evaluated MPV, an indicator of platelet reactivity, in patients with PFO. Patients and methods The study group consisted of 77 patients with PFO (46 women, 31 men, mean age 34.2  23.0 years) admitted to our university hospital between 2008 and 2012. An age and sex-matched control group was composed of 43 healthy volunteers (27 women, 16 men with a mean age 37.3  12.4 years). The study was approved by the institutional ethics committee and all patients gave their informed consent. Exclusion criteria were moderate to severe mitral and/ or aortic valve disease, coronary artery disease, acute coronary syndromes, left ventricular systolic dysfunction, atrial fibrillation, hypertension, diabetes mellitus, dysli- pidemia, history of renal or liver disease, malignancy, venous thrombosis, systemic or pulmonary embolism, congenital hemorrhagic disease, thrombocytopenia, thrombocytosis, transfusion, acute or chronic inflam- matory disease, autoimmune disease or current use of oral contraceptives, anticoagulant or antiplatelet drugs and statins. Echocardiography Both transthoracic and transesophageal echocardio- graphies (GE VingMed System FiVe, Norway) with tissue harmonics were performed by two experienced investigators. M-mode measurements were obtained from parasternal long-axis view for left atrium diameter, end-diastolic and end-systolic diameters of the left ventricle, septum and posterior wall thickness according to the recommendations of the American Society of Echocardiography. Left ventricular ejection fraction was calculated by Simpson’s method. A transesophageal echocardiography was performed by 7.5-MHz multiplane transducer at 08 (four-chamber view), 458 (aortic short Original article 605 0957-5235 ß 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins DOI:10.1097/MBC.0b013e32836029ee